We have measured dopamine-beta-hydroxylase (DBH) in cerebrospinal fluid (CSF) from psychiatric patients. DBH is the enzyme which catalyzes the conversion of dopamine to norepinephrine; its level in CSF may be an index of central noradrenergic activity. No significant differences have been found among the the mean CSF DBH values for 4 diagnostic groups--primary affective disorder, schizophrenia/schizoaffective disorder, alcoholism, and personality disorders. Preliminary evidence indicates that DBH activity in CSF may be related to mood state and to treatment with psychoactive drugs.